//
// Created by Administrator on 2024/3/25.
//
#include<bits/stdc++.h>

using namespace std;
typedef long long ll;
const ll MOD = 1e9 + 7;
ll f[1001];// f[i] 长度为i，且以0结尾的不含11串的个数
ll g[1001];// g[i] 长度为i，且以1结尾的不含11串的个数

int main() {
    int n;
    cin >> n;
    f[1] = 1;
    g[1] = 1;
    for (int i = 2; i <= n; i++) {
        f[i] = (f[i - 1] + g[i - 1]) % MOD;
        g[i] = f[i - 1];
    }
    cout << (f[n] + g[n]) % MOD;
    return 0;
}